This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Dysfunction of the neuronal microcircuits in the prefrontal cortex is believed to underline the pathogenesis of some major neuropsychiatric disorders, such as schizophrenia. Generation and maintenance of persistent neuronal activity is one of essential features of these prefrontal circuits underlying many prefrontal functions, including working memory. The aims of this project are to investigate 1) the basic synaptic transmission properties in prefrontal microcircuits, 2) synaptic plasticity, especially spike timing-dependent plasticity (STDP), and its interaction with persistent neuronal activity, 3) the modulatory effects of dopaminergic input and underlying molecular mechanisms.